sustainability Article Solar and Shading Potential of Different Configurations of Building Integrated Photovoltaics Used as Shading Devices Considering Hot Climatic Conditions Omar S. Asfour Department of Architecture, King Fahd University of Petroleum and Minerals, P.O. Box 2483, Dhahran 31261, Saudi Arabia; [email protected] or [email protected]; Tel.: +966-13-860-3594; Fax: +966-13-860-3210 Received: 23 October 2018; Accepted: 21 November 2018; Published: 23 November 2018 Abstract: This study investigates the use of building-integrated photovoltaics (BIPVs) as shading devices in hot climates, with reference to the conditions of Saudi Arabia. It used parametric numerical modelling to critically appraise the potential of eight design configurations in this regard, including vertical and horizontal shading devices with different inclination angles. The study assumed that the examined shading devices could be entirely horizontal or vertical on the three exposed facades, which is common practice in architecture. The study found that the examined configurations offered different solar and shading potentials. However, the case of horizontal BIPV shading devices with a 45◦ tilt angle received the highest amount of annual total insolation (104 kWh/m2) and offered effective window shading of 96% of the total window area on average in summer. The study concluded that, unlike the common recommendation of avoiding horizontal shading devices on eastern and western facades, it is possible in countries characterised with high solar altitudes such as Saudi Arabia to use them effectively to generate electricity and provide the required window shading. Keywords: building-integrated photovoltaics (BIPVs); solar energy; shading devices; architecture; Saudi Arabia 1. Introduction In recent decades, researchers have been actively engaged in studying renewable energy technologies, including their potential applications in buildings. These efforts are driven by the insecurity of fossil fuel supplies and the associated negative environmental impacts. One important renewable energy source in this regard is solar energy, which could be effectively used in buildings for water heating and electricity generation. This is even more effective in hot climates due to the abundant availability of solar radiation. One of the most promising technologies in this field is the use of building-integrated photovoltaics (BIPVs) to generate electricity in buildings. The following sections of this literature review provide some details in this regard. The main attention in this context is paid to the potential use of BIPV as shading devices in hot climatic areas such as Saudi Arabia. 1.1. BIPVs Concept and Applications Building-integrated photovoltaics (BIPVs), as opposed to building-applied photovoltaics (BAPVs), are simply photovoltaic (PV) systems that are used as integral parts of the building envelope. In this capacity, BIPV systems share the well-known advantages of BAPV systems such as providing an on-site renewable energy source that is silent, produces no hazardous emissions during operation, and requires relatively little maintenance during its expected lifetime of 20–25 years [1,2]. However, Sustainability 2018, 10, 4373; doi:10.3390/su10124373 www.mdpi.com/journal/sustainability Sustainability 2018, 10, x FOR PEER REVIEW 2 of 15 Sustainability 2018, 10, 4373 2 of 15 providing an on-site renewable energy source that is silent, produces no hazardous emissions during operation, and requires relatively little maintenance during its expected lifetime of 20–25 years [1,2]. 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Further Furthe detailsr details on the on use the of use BIPVs of BIPVs as shading as shad devicesing devices is provided is provided in Section in Section 1.3 of this 1.3 literatureof this literature review. review. Pitched Roofs Flat Roofs Shading Devices Curtain Walls FigureFigure 1.1. SomeSome integrationintegration formsforms ofof photovoltaicsphotovoltaics intointo buildingbuilding facadesfacades [[15].15]. 1.2.1.2. BIPVsBIPVs Status in Saudi Arabia TheThe useuse of of BIPV BIPV systems systems is greatly is greatly related related to the localto the culture, local architecture,culture, architecture, and climatic and conditions climatic ofconditions each country. of each Several country. studies Several could studies be found could inbe thisfound context in this for context some for specific somecountries, specific countries, such as Bahrainsuch as Bahrain [9], Egypt [9], [16 Egypt], India [16], [17 India], Malaysia [17], Malaysia [18], Italy [18], [19 ],Italy and [19], Canada and [Canada20]. Saudi [20]. Arabia Saudi is Arabia an Arab is countryan Arab thatcountry has thethat largest has the oil largest reserves oil inreserves the world in the (about world 25%). (about It is 25%). considered It is considered the fastest the growing fastest electricitygrowing electricity consumer consumer in the Middle in the East. Middle In 2005, East. it In was 2005, the it world’s was the 15th world’s largest 15th consumer largest consumer of primary of energy,primary of energy, which overof which 60% over was petroleum-based60% was petroleum-bas [21]. Despiteed [21]. the Despite fact that the oil fact availability that oil availability is the main is drivingthe main power driving of power the Saudi of the economy Saudi economy so far, its so sustainability far, its sustainability is questioned is questioned considering considering the global the Sustainability 2018, 10, 4373 3 of 15 concern over fossil fuel supplies [22]. Saudi Arabia has considered this issue through the adoption of Saudi Vision 2030. One of the main objectives of this vision is to reduce Saudi Arabia’s dependence on oil and to diversify its economy in a more sustainable way. The Vision has set an initial target of generating 9.5 gigawatts of renewable energy in this regard. It also aims to localise a significant portion of the renewable energy value chain in the Saudi economy, including research and development and manufacturing